Airplane



l o. WRIGHT ET'AL AIRPLANE Filed May 31,

3 vSheets-Smet l Patented Aug. 1.2, 1924.

UNITED STATES PATENT oFElcE.

ORVILLE WRIGHT AND JAMES M. Ha JACOBS, OF DAYTON, OHIO, ASSIGNORS TO DAY- TON-WRIGHT COMPANY, OF DAYTON, OHIO, A CORPORATION OFDELAWARE.

AIRPLANE.

Application filed May 31, 1921. Serial No. 474,046.

To all whom t may concern:

Be it known that we, ORVILLE WRIGHT and JAMES M. H. JACOBS, citizens of the United States of America, residing at Dayton, county of Montgomery, and State of Ohio, have invented certain new and useful Improvements in Airplanes, of which the following is a full, clear, and exact description.

The present invention relates to airplanes and particularly to areofoils used in the' construction thereof, and also to the control of aerofoils.

It is among the objects of the present invention greatly to increase the lift of the aerofoil thereby permitting considerably lower flying speeds than heretofore possible.

A further object is to increase the lift of the aerofoil without making it necessary to fly with the fuselage of the airplane inclined to the horizontal a relatively large amount. This permits the airplane to take off or land with'its fuselage in a more nearly horizontal position and hence a landing chassis of lower height may be used.

A further object is to more nearly equalize the drift of the two opposite wings of an airplane while maintaining lateral balance.

Further objects and advantages of the present invention will be` apparent from the following description, reference being had to the accompanying drawings, wherein preferred forms of embodiments of the invention are clearly shown.

In the drawings Figs. 1, 2 and 3, show the general nature of the flow about a conventional aerofoil in three positions, respectively, normal flying position, greatest lift position and when at an angle exceeding that for greatest lift;

Fig. 4 shows the profile of anaerofoil embodying the present invention disposed to produce a greater lift than could be obtained with lthe conventional type, said aerofoil having a flap forming apart of its lower surface, the upper surface remaining fixed;

Fig. 5 shows the profile of this areofoil disposed to produce a lesserflift;

Fig. 6l Shows the same aerofoil in normal flying position;

Figs. 7 to 10 show another form of the invention shown in Figs. 4 to 6, in which portions of both the upper and lower surfaces of the aerofoil include flaps;

Fig. 11 shows a modification 4wherein the lower flap is hinged upon the upper flap;

Fig. 12 is a fragmentary perspective view of an airplane having aerofoil panels and coitrols embodying the present invention; an

Fig. 13 is a fragmentary sectional view of aerofoil flap construction.

Referring to Figs. 1, 2 and 3,2() desig nates the profile of a conventional aerofoil having an upper Surface represented by line 21 and a lower surface represented by line 22, said lines joining at the leading and trailing edges of the aerofoil 20. In Figs. 1. to 6, line 23 denotes the normal direction of air current assumed to be the horizontal.

It is generally understood in aeronautics that the smaller the angle of incidence of a given aerofoil, the smaller the lift within the range of flying'angles. Ithas also been established that the greater the angle of incidence of the same aerofoil, the greater the lift up toa certain well defined limit. This limit is that angle at which the air flow over the upper surface of the aerofoil ceases to be in the form of a continuous stream and commences to eddy above the rear portion. These premises are illustrated graphically in Figs. 1, 2 and 3 of the drawings.

It will be noted that in Figs. 1 and 2, the air streams represented by lines A, A", and B and B are substantially smooth flowing currents divided by the front edge of the aerofoil 20 and passing along the upper and lower surfaces 21 and 22 fairly close thereto.

In Fig. 2 the stream B is illustrated as fol- ,lowing a path over the trailing edge at a little distance therefrom. This illustration depicts very clearly what is actually the case and the zone marked low pressure is at a pressure which is Somewhat below atmospheric. It is understood that the aero-"v,

foil is lifted due to the difference in pressure on the upper and lower surfaces.

In Fig. 2, the aerofoil is shown at position of greatest lift.l Whatthe angle of incidence is for this position will of course depend on 'the aspectratio of the particular aerofoil aspect ratio.

chosen for illustration. If the angle of incidence exceeds a certain value then the low pressure zone is partially destroyed as shown in Fig. 3. The upper current line of 2 now breaks into a series of eddles C, 1, C2, C1., etc., which swirl off into the air leaving new ones to be continually formed. Since the low pressure above the surface 2 1 is partially` destroyed, the lift of the aerofoil decreases. This certain value of the angle of incidence at which the air stream above the upper'surface 21 breaks is called the critical angle or burble point.

It is also well known that the lift of an aerofoil may be increased by increasing its camber within certain limits inl excess of which the upper air stream will break into eddies and the partial vacuum above the vupper surface Wil'l be destroyed. One form of the present invention discloses means and a method for increasing lift by changing the camber not of the whole aerofoil, but only of its lower surface leaving the camber of the upper surface fixed, that is having the conventional form. Fig. 6 shows the profile of an aerofoil 30'having an upper surface 31 anda lower surface including a lea-ding portion 32 and a trailing portion 33 which is carried by a lap 34 pivoted at 435. When flap'il' is folded the aerofoil takes the con vcntional form as' shown in Fig. 1.

In Fig. 4, the aerofoil is inclined and the flap 84is dropped to produce a very great lift. the inclination and the spread of the flap depending on the type of section and E denotes theI upper stream line which forms a swirl at E not above the surface 31 but well beyond the trailingedge of the aerofoil, F denotes the lower stream line which forms a swirl also beyond the trailing edge forming similar eddies as the eddies like E drift away and are dissipated. The low pressure Zone marked in Fig. 4 remains undestroyed because the camber of upper surface 31 is not increased and the surface 31 stays in position Ato prevent the breaking of the upper stream line E into eddies above the surface 31. The eddies are not formed except back of the trailing edge where their presence does not affect the lift. The zone above flap 34 is-practically a dead air space so far as known. As the static pressure on the upper and lower sides of this zone remains the same there is practically no effect on the lift. By actual test of sev eral types of sections it has been found that the lift of an aerofoil embodying the present invention is Very much greater than can be obtained with the conventional type.

From the foregoing it is apparent that th aerofoil embodying the present invention is of such form as to permit greatly increasing the angle of incidence of the underside of the aerofoil without inclining to a very large extent the part of the aerofoil directly attached to the fuselage. The advanta e which results is that the lift may be great y tion of the left wing whi c the right wing may be disposed as shown in Fig. 45 to produce a lesser lift. creases with the lift, it is desirable to provide means for more nearly equalizing the drift on both sides of an airplane. The form of the invention now to be described is particularly directed toward maintaining equal drift on both sides of the airplane while maintaining lateral balance.

Referring to Figs. 7 and 12, showing a practical ap lication of the invention to an airplane, d) in flight by left' wing 51 and right wing 51 which are similarly constructed. Ting 51 includes a portion 52 fixed to fuselage 53, and flaps 54. and -hinged at 56. Flap 54, the lower flap, corresponds to flap 34 of Fig. a, and flap 55, the upper flap, operates as an aileron in conjunction with the lower flap. Flaps 54 and 55 when folded and in the position shown in Fig. 7 form with the portion 52, the conventional type of aerofoil` flaps 54 and 55 forming the trailing portions of the aerofoil. Flaps 54 and 55 are pref erably hinged back of the median line of the aerofoil and intermediate the upper and lower surfaces.

Flap 54 is providedV with horn 57, and flap 55 with horns 58 and 59 withwhich controlling cables are connected. Spring connects flaps 54 and .55, spring 60 being at least strong enough to overcome the Weight of flap 54. Air pressure may be depended upon to force'flap 54 against flap 55 when `the horn 57 is released.

The prime numbered parts of wing 51. correspond to the similarly numbered parts of Wing 51.

Horn 57 isconnected by cable 6l with winding drum 62 which is mounted on shaft 63 carrying sprocket 64/connected by chain 65 with sprocket 66. Sprocket 66 is mounted on shaft 67 carrying crank 68 and ratchet 69, cooperating with pawl 70. Elements 64. 65 and 66 are shown as belt connected for sake of clearness, but it will be understood that preferably these elements are positively But since the drift inesignatcs an airplane supported lll) geared as described. It will also be understood that the windi power operated, if deslred, that is, driven by the airplane engine or by a separate motor. The control stick 90 may be power operatedif desired. The horn 57 is connected with drum 62 b a similar cable 61. Before cables 61 an 61 reach the drum 62 they must pass, respectively, around pulleys 71 and 72 and 71 and 72', and then pass together around pulley 73 supported by aileron control shaft 74 and then together through said shaft 74.

Shaft 74 has bearings at 75 and 76 and carries sector 77 which supports pulleys 72 and 72. Wire 80 which passes aro'und pulley 81 connects horn 58 with sector 77 preferably adjacent the axis of pulley 725 and wire 80 passing around pulley 81 similarly connects horn 58 and sector 77. Wire 82 passingaround pulleys 83 and 83 connects horns 59 and 59.

Control stick 90 is pivoted at 91 upon shaft 74 and is connected at 92 and 93 respectively with elevator control cables 94 and 95. It is apparent that sidewise movement of stick 90 will operate they iiaps 55 and as ailerons inthe usual manner. By tying the lower aps 54 and 54 res ectively with 55 and 55', the two sets of aps 54-55 and 54-55 will together operate as ailerons, either when flaps 54-55 and 54'- 155f are closed or when opened to increase the By turning the crank 67 counter-clockwise the drum 62 will wind up cables 61 and 61 at the same time and equal amounts, thereby separating the flaps 54-55 and 54-55, respectively, simultaneously and equal amounts. This is desirable since the lift on both sides of the fuselage should be the same when flying straight ahead. This arrangement of flaps is shown in Figs. 8 and 12, the upper flaps 55 and 55 remaining in normal position. The pawl 70. is intended to maintain ratchet 69 and therefore flaps 54 and 54 in the desired position of adjustment with respect to the upper flaps. Of course l for decreasing the angle between flaps 54- 55 and 54-55 the crank 67 must be turned in the opposite or clockwise direction.

If the control stick is moved in the direcl tion of arrow 96 the flaps 54 and 55 will be moved down to increase the lift on the left side as shown in Fig. 9 while flaps 54 and 55 will move up as shownin Fig. 10 to decrease the lift on the right side. In this manner the airplane is caused to maintain the lateral balance while at the same timegiving more nearly equal drift :on both wings. ln'normal flight both pairs'of flaps return to the position shown in Fig. 8 with 'the angle between the flaps remaining the same.

Therefore it is seen that the camber ofthe drum 62 may be' without changin lower surface of the aerofoil may be changed the camber of the u per surface Simp y y operating the win g drum. Then the camberof both surfaces of the aerofoil can be changedA Whether or not .the winding drum is stationary and this latter adjustment can be made without changing the setting made by the first adjustment.

While in Fig. 12, the wings of the airplane are shown as having flaps extending the whole length of wing portions fixed to the fuselage, it is rto be understood that certain trailing portions of the wings may be relativelyfixed while lother portions comprise flaps constructed and arranged in accordance with the present invention. In other words, the wings may be said to have flaps forming part or all of the trailing portions thereof.

Fig. 11 is a modified form of aerofoil in which the lower flap 54 is hinged atA a different point 56*l from the hinge 56 of llap 55,l

Fig. 13 shows one manner of constructing the. flaps 54 and 55. Since the space between these fiaps has no function the inner surfaces of these. `flaps need no covering, therefore the ribs of the ilaps may be made nearly as deep as the total depth of both flaps except where joined to the spars. In Fig. 13, flap 54 includes spar 100 sup-port- `ing a plurality of overhanging ribs 101 covered by covering 102. Flap 55 includesr spar 103 supporting a plurality of overhanging ribs 104 covered by covering 105. When thev flaps 'are folded these ribs 101 andv 104 telescope past one another somewhat as the blades of shears. The advantage is that the flaps may be more substantially constructed than where the rib depth is about equal to the ldepth of the flap.

While the `forms of mechanism herein shown -and described, constitute preferred forms of embodiment of the present invention, it is to beunderstood that other forms might be adopted all coming within the scope of the claims which follow.

What we claim is as follows:

. 1,-In an aerofoil, means for changing either the camber of its upper surface or the camber of its lower surface independently of one another.

2. In an airplane control, the combination with an aerofoil having'flaps forming, respectively, the trailing portions of its upper and lower surfaces; of means for movin said flaps relative to each other, and mea-ns for moving said flaps relative to the aerofoil while keeping the angle between the flaps constant.

said flaps; and means for moving said aps l with respec spectively, the trailing ortions of its upperand lower surfaces; o means for moving the lower flap without moving the upper fla In an air lane control, the combination with an airp ane havin right and left wings; of means .for simu taneously increasing the camber of only the lower surfaces of said wings; and other means for increasin the camber of the lower surface of said le wing while decreasing thecamber of the lower surface of said right wing and vice versa.

6. In an airplane control, the combination -with an airplane having right and left wings; of means for simultaneously increasing the camber of only the lower surfaces of said wings; and other means for increasin the camber ofthe upper surface of said leg wing while decreasing the camber of the upper surface of said right wing and vice versa.

7. In an airplane control, the combination A with an airplane having right and left wings; of means for simultaneously increasing the camber of only the lower surfaces of said wings; and other means for increasing the camber of the upper and lower surfaces of said left wing while decreasing the camber of the upper and lower surfaces of the right wing and vice versa.

8. In an airplane control, the combination with an airplane having right and left wings, each of said wings having upper and lower flaps forming, respectively, trailing portions of the upper and lower surfaces of said wings; of means for movingy the lower flaps simultaneously and equal amounts in the same direction without moving the upper liaps, and means for moving the upper ila-ps.

9. In an airplane control, the combination with an airplane having right and left wings, each of said wings having upper and lower ilaps forming, respectively, trailing portions of the upper and lower surfaces of said wings; of mean'sv for moving the lower iaps independently of the upper flaps; and means for moving the upper flaps on the right and left wings in opposite directions.

10. In an airplane control, the combination with an airplane having right and left wings, each of said wings having'upper and lower ila-ps forming, res ectively, trailing portions of the upper an lower surfaces of said wings; of means for moving the lower flaps independentlv of the upper flaps; and a second means for moving the upper and lower flaps together.

ALeonesa flaps independently ofthe uppler flaps; and y a second means for moving t e upper and lower fla stogether while maintaining said iaps in xed an lar relation.

12. In an airp ane control, the combination with an airplane having right and left wings, each of said wings having upper and lower flaps forming, respectively, trailin portions of the upper and lower surfaces o said wings; of means for moving said lower flaps; and means for moving the upper and lower flaps on the right wing in one direction and the upper and lower flaps on the left wing in the opposite direction and vice versa.

13. In an airplane control, the combination with an airplane having right and left wings, each of said wings having upper and lower aps forming, res actively, trailing portions of the upper an lower surfaces of said wings; of means for moving the lower 14. In an airplane control, the combina-v tion with an airplane having right and left wings, each of said wings having upper and lower flaps, forming respectively, trailing portions of the upper and lower surfaces of said wings;of means for moving the lower iaps on both sides of the airplane simultaneously in the same direction; and means for moving the upper and lower flaps on one side of the airplane in one direction and the upper and lower flaps on the other side of the airplane in the opposite direction.

15. In a-n airplane control, the combination with an airplane having right and left wings, each of said wings having upper and lower flaps, forming respectively, trailing portions of the upper and lower surfaces of said wings; of means for moving the lower flaps on both sides of the airplane simultaneously in the same direction; and means for moving the iaps on one side of the airplane in one direction and the flaps on the other side of the airplane in the opposite direction while maintaining fixed the angular relation between the sets of upper and lower flaps on both sides of the airplane simultaneously equal amounts in the same direction; and means fox-moving the flaps on one In testimony whereof` we hereto affix our signatures.

side of the airplane in one direction and the i ORVILLE WRIGHT 5 flaps on the other side of the airplane in the JAMES M' H' JACOBS' opposite direction while maintaining fixed Witness: the angulai` relation between the sets of A. C. LEHMAN.

upper and lower flaps. 

